Post-traumatic Stress Disorder (PTSD)
Definition
Post-Traumatic Stress Disorder, PTSD, is an anxiety disorder that can develop after exposure to a terrifying event or ordeal in which grave physical harm occurred or was threatened. Traumatic events that may trigger PTSD include violent personal assaults, natural or human-caused disasters, accidents, or military combat.
Signs and Symptoms
Post-traumatic stress disorder (PTSD) develops after a terrifying ordeal that involved physical harm or the threat of physical harm. The person who develops PTSD may have been the one who was harmed, the harm may have happened to a loved one, or the person may have witnessed a harmful event that happened to loved ones or strangers.
PTSD was first brought to public attention in relation to war veterans, but it can result from a variety of traumatic incidents, such as mugging, rape, torture, being kidnapped or held captive, child abuse, car accidents, train wrecks, plane crashes, bombings, or natural disasters such as floods or earthquakes.
People with PTSD may startle easily, become emotionally numb (especially in relation to people with whom they used to be close), lose interest in things they used to enjoy, have trouble feeling affectionate, be irritable, become more aggressive, or even become violent. They avoid situations that remind them of the original incident, and anniversaries of the incident are often very difficult. PTSD symptoms seem to be worse if the event that triggered them was deliberately initiated by another person, as in a mugging or a kidnapping. Most people with PTSD repeatedly relive the trauma in their thoughts during the day and in nightmares when they sleep. These are called flashbacks. Flashbacks may consist of images, sounds, smells, or feelings, and are often triggered by ordinary occurrences, such as a door slamming or a car backfiring on the street. A person having a flashback may lose touch with reality and believe that the traumatic incident is happening all over again.
Not every traumatized person develops full-blown or even minor PTSD. Symptoms usually begin within 3 months of the incident but occasionally emerge years afterward. They must last more than a month to be considered PTSD. The course of the illness varies. Some people recover within 6 months, while others have symptoms that last much longer. In some people, the condition becomes chronic.
Causes
Research is continuing to reveal factors that may lead to PTSD. People who have been abused as children or who have had other previous traumatic experiences are more likely to develop the disorder. In addition, it used to be believed that people who tend to be emotionally numb after a trauma were showing a healthy response; but now some researchers suspect that people who experience this emotional distancing may be more prone to PTSD.
Studies in animals and humans have focused on pinpointing the specific brain areas and circuits involved in anxiety and fear, which are important for understanding anxiety disorders such as PTSD. Fear, an emotion that evolved to deal with danger, causes an automatic, rapid protective response in many systems of the body. It has been found that the fear response is coordinated by a small structure deep inside the brain, called the amygdala. The amygdala, although relatively small, is a very complicated structure, and recent research suggests that different anxiety disorders may be associated with abnormal activation of the amygdala.
People with PTSD tend to have abnormal levels of key hormones involved in response to stress. When people are in danger, they produce high levels of natural opiates, which can temporarily mask pain. Scientists have found that people with PTSD continue to produce those higher levels even after the danger has passed; this may lead to the blunted emotions associated with the condition.
Some studies have shown that cortisol levels are lower than normal and epinephrine and norepinephrine are higher than normal. Norepinephrine is a neurotransmitter released during stress, and one of its functions is to activate the hippocampus, the brain structure involved with organizing and storing information for long-term memory. This action of norepinephrine is thought to be one reason why people generally can remember emotionally arousing events better than other situations. Under the extreme stress of trauma, norepinephrine may act longer or more intensely on the hippocampus, leading to the formation of abnormally strong memories that are then experienced as flashbacks or intrusions. Since cortisol normally limits norepinephrine activation, low cortisol levels may represent a significant risk factor for developing PTSD.
Research to understand these neurotransmitter systems involved in memories of emotionally charged events may lead to the discovery of drugs or psychosocial interventions that, if given early, could block the development of PTSD symptoms.
Occurrence
PTSD affects about 7.7 million American adults, but it can occur at any age, including childhood. Women are more likely to develop PTSD than men, and there is some evidence that susceptibility to the disorder may run in families. PTSD is often accompanied by depression, substance abuse, or one or more of the other anxiety disorders.